As of last week the Ministry of Health had received about 3500 queries from people who were having trouble enabling Bluetooth tracing. The most common complaint was from users of iPhone 6 and older, making up about a third of the total.
The ministry said it was looking at what was needed to update the app.
"Recently, Apple released support for the exposure notifications feature that enables Bluetooth tracing in iOS 12.5, which will run on iPhone 6," a spokesperson said.
"We are looking at what we need to do to update the NZ Covid Tracer app to support Bluetooth tracing on these older iPhones, but we don't currently have a timeframe for this."
The ministry recommended that people with an Android 5 device use the Rippl app to scan QR codes, and keep a digital diary.
"This is a privately developed app, but it is also integrated with our contact tracing systems," the spokesperson added.
Details on enabling Bluetooth are available on the ministry's website.